1. Field of the Invention
The present invention relates to a vehicle lamp unit configured such that light from a light emitting device is emitted forward from a transparent member disposed in front of the light emitting device.
2. Related Art
A related art lamp unit has a light emitting device disposed adjacent to a point on an optical axis extending in the front-rear direction of a vehicle. The light emitting device is arranged such that its light emitting surface faces forward. The light from the light emitting device is emitted forward from a transparent member disposed in front of the light emitting device (see, e.g., JP 2005-11704 A).
More specifically, the light emitted from the light emitting device entered the transparent member is internally reflected by the front surface of the transparent member. The light reflected by the front surface is internally reflected again by the rear surface of the transparent member, and is emitted from another portion of the front surface. The central area of the front surface of the transparent member has a mirrored surface to internally reflect the light from the light emitting device.
According to this configuration, a slim headlamp can be provided. Further, by arranging the light emitting device such that the bottom side edge of the light emitting surface of the light emitting device is disposed on and along the horizontal line perpendicular to the optical axis, a light distribution pattern having a horizontal cutoff line at its upper end can be formed.
However, the related art lamp unit can only form a linear cutoff line extending in a single direction.
Therefore, to provide a headlamp capable of forming a low beam light distribution pattern, a lamp unit for forming a horizontal cutoff line and a lamp unit for forming an oblique cutoff line are used together.
Further, the front surface of the transparent member is flat and is perpendicular to the optical axis. Therefore, when arranging the related art lamp unit in a headlamp having a rearwardly slanted transparent cover, the layout of the lamp unit inside the headlamp is limited to the extent that the perpendicular front surface of the transparent member does not hit the transparent cover in front.